Boiler furnace



Oct. l5, 1929. `G. T. L ADD 1,731,427

BOILER FRNACEv Filed March 26, 1926 5 Sheets-Sheet 1 nventoz Mge fm @l @au v 0d, 15, 1929. G. T. LADD 1,731,427

BO ILER FURNACE Filed March 26, 1926 5 Sheets-Sheet 2 Suva/lic:

Oct. 15, 1929. G. T. LADD 1,731,427

' BOILER FURNACE Filed March 26, 1926 3 Sheets-Sheet 3 5mm/nto@ Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE GEORGE T. LADD, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO LADD WATER TUBE BOILER COMPANY, OF NEW YORK, N. Y., A CORPORATION 0F DELAWARE BOILER FURNACE Application led March 26, 1926. Serial No. 97,505.

This invention relates to improvements in boiler-furnaces, and is particularly useful where the fuel to be burned in the same is in finely divided form, as, for example, in the form of pulverized coal. l

One of the primary objects of the invention is to provide a boiler-furnace, the capacity of which is relatively very large, as compared to its size.

Another object of the invention is to at one and the same time increase the steaming capacity of theboiler and obviate brick maintenance difficulties.

Another object of the invention is to so dispose evaporating elements as to make it possible to burn the pulverized coal with a flame of higher temperature than heretofore.

The foregoing, together with such other objects as may hereinafter appear, or are incident to my invention, I obtain by means of a construction which I have illustrated in the prefered form in the accompanying drawings, wherein- Fig. 1 is a vertical section through a boilerfurnace embodying my improvements.

Fig. 2 is a horizontal section through the boiler-furnace of Fig. 1, and l Fig. 3 is a vertical section through a modified form of the boiler-furnace of my invention.

Referring now to Figs. 1 and 2, the reference character A denotes the combustion chamber. At the rear of the chamber is the boiler proper B which is composed of an upper druln 7 and a lower or mud drum 8 and the `three banks of verticallydisposed tubes 9, 10, and 11, such tubes being suitably baffled, preferably in three passes. The front wall 12 of the chamber is shaded by a row of spaced vertical tubes 13, the upper ends of which are ,connected to the drum 14, and the lower ends of which pass through the chamber wall for connection into the header 15. The drum 14 is connected to the drum 7 by a plurality of pipes 16, and the header15 yis connected to the drum 8 by large pipes 17 arranged exteriorly of the chamber.

The combustion s ace isthus defined on two sides by the tu es 13 and the bank of tubes 9, and the pulverized coal is admitted preferably in a downward direction into the combustion space through the arch 18 by means of one or more burners 19.

The coal preferably with all of the air for combustion is supplied through the burners under conditions to produce violent combustion with a short and intensely hot flame, combustion being normally completed at a point well above the ash pit 20 below the combustion' space. In the preferred operation with the short intensely hot flame described, combustion is largely completed before the downward momentum of the fuel, and the combustible gases liberated, is overcome by the draft, except at high rates of firing, in consequence of which, for the most part, only the incombustible gaseous products of combustion sweep over and through the bank of tubes 9 on their way to the second pass of the boiler. The tubes 13 and 9 being thus exposed to radiant heat, as well as to convection, transmit heat at a very high rate, and the boiler has a high steaming capacity in relation to its size. The flow upwardly through the pipes 13 will be very rapid, and in consequence of the high rate of heat absorption, these tubes will protect the front wall. For further protection the refractory bricks 20 may be slipped between the tubes 13 in assemblage, as indicated in Fig. 2. These bricks will have extended life by virtue of their contact with the tubes which will absorb heat therefrom.

In the modification shown in Fig. 3, substantially the same general construction is employed, with the exception that the boiler proper is 0f the inclined water tube type. The front wall, as before, is shaded by the tubes 13, but, in addition, I arrange a water screen of spaced tubes 21 over the ash pit 22, such tubes having their upper ends connected into the header 1,5, and their lower and also adding greatly to the evaporation of the boiler. I also provide a row of tubes. 26, in advance of the bridge wall 27 to protectthe latter and to add to the steaming capacity of the boiler. These tubes ,26 are connected to the mud drum and to the header 23. In the arrangement of Fig. 3 there is a much greater amount of evaporating surface exposed to radiant heat, and with a flame of intense temperature the rate of heat transmission will be very rapid. If desired, the fuel may be burned with va longer name with the arrangement in Fig. 3 than is the case with the arrangement in Fig. 1.

1. In combination, a combustion chamber having a bridge wall at the rear, a boiler over said bridge wall having an upper and lower drum, a row of upright tubes subject to heat within the chamber extending over said bridge wall and connected at their upper ends to sald lower drum, a tubular water screen in the lower portion of the combustion chamber, and common downcomer means from the boiler directly connected to the lower end of said upright tubes and to one end of the tubes A of the water screen and an upcomer connection for the water screen.

.2. In combination, a combustion chamber having a bridge wall at the rear, a boiler over said bridge wall having an upper and lower drum, a row of upright tubes subject to heat within the chamber extending over ends to said lower drum, a tubular water screen in the lower portion of the combustion chamber, a header common to the lower end of the upright tubes and to one end of the tubes of the water screen, a. downcomer from the boiler connected to said header and an upcomer for the water screen.

3. In combination, a combustion chamber, a boiler at the rear thereof having an upper and a lower drum with connecting tubes, certain of which are subject to radiant heat, the others being subject to the heat of convection, a tubular water wall defining the combustion space at the front, a drum into which the upper ends of said tubes are connected, a connection between said drum and the upper drum, a header into which the lower ends of the tubes of the water wall are connected, means for supplying water to said header comprising an upcomer connection leading thereto and communicating with the lower drum of the boiler and means for introducing fuel and air to be burned in suspension in said combustion chamber.

4. In combination, a combustion chamber, a boiler at the rear thereof having an upper and .a lower drum with connecting tubes, certain of -which are subject to radiant heat, the.

others being subject to the heat of convection,

a tubular water wall defining the combustion space at the front, a'drum into which the upper ends of said tubes are connected, a connection between said drum and the upper drum, a header into which the lower ends of the tubes of the water wall are connected, means for supplying water to said header comprising an upcomer connection leading thereto and communicating with the lower drum of the boiler, said connection comprising fairly widely spaced tubes extending across the chamber well above the floor thereof and means for introducing fuel and air to be burned in suspension in said combustion chamber.

5. In combination, a combustion chamber having a bridge wall at the rear, a boiler over said bridge wall having an upper and lower drum, a row of upright tubes subject to heat within the chamber extending over said bridge wall and connected at their upperends to said lower drum, a tubular water screen in the lower portion of the combustion chamber, and common downcomer means from the boiler connected to the lower end of said u right tubes and to one end of the tubes of e water screen and an upcomer connection from the water screen, comprising a row of upright tubes extending over the front wall of the chamber with their upper ends connected to said upper drum.

In testimony whereof I have hereunto signed my` name.

GEO. T. LADD. Y

said bridge wall and connected at their upper -iao 

